This study intends to explore the therapeutic effect of PCSK9i Evolocumab on atherosclerotic plaques in cerebral arteries (including carotid and vertebral arteries) compared with intensive statin treatment, and monitor the pathological properties of carotid/vertebral artery plaques with OCT technology. At the same time, three-dimensional ultrasound and high-resolution magnetic resonance are used to explore the new mechanism of pathological changes of cerebral atherosclerotic plaques in a multidimensional manner.

Inclusion Criteria:

1. Age ≥ 18 years old, regardless of sex;
2. Cerebrovascular angiography examination was performed, and the imaging characteristics were consistent with: 1) The stenosis degree of internal carotid artery (starting from C1 segment) or vertebral artery (starting from vertebral artery to V4 segment) was 20%-69%; 2) The target vessel for imaging has not undergone or intends to undergo revascularization and must be available for OCT imaging catheter;
3. Participants who understand and sign the informed consent form voluntarily.

Exclusion Criteria:

1. Intolerant to both atorvastatin and rosuvastatin;
2. History of major surgery or endovascular treatment within 3 months prior to the screening period;
3. Arterial stenosis or occlusion not caused by atherosclerosis, such as arterial dissection, moya-moya disease, vasculitis, radiation vascular disease, or fibromuscular dysplasia;
4. Abnormal liver function (ALT > 3 times the upper limit of normal);
5. Renal dysfunction (glomerular filtration rate (eGFR) <45 mL/min/1.73m2 at screening);
6. Thrombocytopenia (PLT<100G/L);
7. The expected survival time is not more than 6 months;
8. Other known serious life-threatening disease (such as hematologic disease, malignancy), unstable vital signs or need for continuous monitoring, or moribund state during screening;
9. Patients have been included in other studies that conflict with this study;
10. Known sensitivity to any of the products or components to be administered during dosing;
11. Pregnant, breastfeeding or planning pregnancy, and other conditions that the investigator considers the patient unsuitable for enrollment;
12. Other conditions that the investigator considered inappropriate for enrollment.